Corner edge roll

ABSTRACT

The invention relates to a method and an apparatus for forming and applying edging material to the corners of ductwork and other conduit structures.

FIELD OF THE INVENTION

This invention relates to insulating ductwork. More specifically, theinvention relates to forming lineal corner edging on insulated ductworkand similar structures.

BACKGROUND OF THE INVENTION

It has been the practice in the insulation of heating and airconditioning ductwork to seal the corners of the ducts, whether straightor curved. Typically, ninety degree angle edging made of either sheetmetal, plastic or even paper has been used. The insulation industry hastraditionally used tin (plated) edges 2"×2" on corners of ductwork,scroll fans and other essentially square edges. These tin plated edgesare held in place with tape or contact adhesive which can be brushapplied. Thereafter canvas, plastic, or other suitable decorative fabricis stretched around the structure and glued in place. In the case ofcanvas, further coatings are painted on to shrink the canvas to a tightfit and seal it to provide an attractive finish. Tin edges or galvanizedsheet metal are generally made of approximately twenty-four gauge(0.023") thick material.

Murasho Co. Ltd. offers an edging material that is formed in a metalroll consisting of a flat surface with overlapping discrete segmentsdepending from the flat surface at a ninety degree angle. The discretesegments facilitate application of the flat surface on contoured edges.The Murasho product is identified as Roll Kiku-za or squeezed sheet.Similarly, Zeston (Manville Corporation) has marketed a metal endcapping product that is essentially the same. A need has arisen for aninexpensive, easy to apply corner edge, starting at 11/2"×11/2" andgoing up to 3"×3" to accommodate the normal insulation thicknesses usedon ductwork and similar structures that are generally 1" to 2" thick (ormore).

SUMMARY OF THE INVENTION

It is an objective of the invention to provide edging material for thecorners of ductwork and other conduit structures formed with square orsomewhat square corners.

It is another object of the present invention to provide polyvinylchloride edging for ducting.

It is a further object of the invention to provide a process formanufacturing polyvinyl chloride edging material particularly wellsuited for sealing the corners of ducting and similar structures.

Accordingly, a flat polyvinyl chloride strip is provided with adhesiveon one side, release paper covering the adhesive, and an embossed scoreline linearly disposed over the length of the strip on the adhesiveside. The release paper is severed at the score line to provide twodiscrete strips of release paper.

Application of the strip to corner edges proceeds by cutting the stripto the length desired, bending the strip down its entire length, on thescore line, to a 90° angle, removing one of the two release paperstrips, adhering the exposed adhesive portion of the strip to the corneredge. The second strip of release paper is then removed and this portionof the strip is pushed down and adhered in place resulting in a 90° (orother angle desired) straight corner edge that covers and seals any rawedges. Where ducts or equipment that are to be edged, turn away from astraight direction, silts can be scissor cut perpendicular to the lengthof the strip, up to the score line to form segments that are foldedalong the score line and adhered to the adjacent surface, on the insideradius curves of the article being edged and to itself.

DESCRIPTION OF THE DRAWINGS

The subject invention will be better understood when viewed with thefollowing drawings wherein:

FIG. 1 is a plan view of the edge strip of the present invention;

FIG. 2 is a sectional elevational view of the invention applied to onesurface of ducting;

FIG. 3 is the edging material of FIG. 2 shown fully applied to theducting;

FIG. 4 is a schematic of the process equipment shown forming the edgingmaterial of the subject invention;

FIG. 5 is a sectional view of the embossing roll assembly taken throughline 5--5 of FIG. 4;

FIG. 6 is a variation of the process for forming the edging material ofthe subject invention; and

FIG. 7 is the edging material of FIG. 1 applied to an insulated pipe.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention has application in any environment in which angled cornersare required to be sealed. However, the present invention will bedescribed principally in the environment of heating, ventilation and airconditioning ducting.

As best seen in FIG. 1, the present invention is comprised of a flatstrip of polyvinyl chloride edging material 2 having a centrallydisposed linear score line 4; a layer of adhesive formed on the adhesiveside 8 of the strip on which the score line 4 is located and optionalseparate release paper strips 12 and 14 to maintain the adhesive layerin an unexposed condition until application of the edging material 2 tothe edge to be sealed. The score line 4 facilitates the bending of thestrip edging material into separate regions 5 and 7.

As seen in FIG. 2, the strip is applied to one surface 16 adjacent tothe edge 18 being sealed, in this case ducting 20, after removal of astrip of release paper 12. Thereafter, the strip of release paper 14 isremoved and the section of the edging material extending beyond theadhered surface is then cut into discrete segments 22 separated by thecut slits 24. The discrete segments 22 are rotated around the score line4 and the exposed adhesive surfaces of the discrete segments 22 arepressed against the opposite or complementary surface 26 of the ducting20 to provide a seal at the duct edge 18, best seen in FIG. 3.

The process of forming the edging strip 2 is best seen in FIG. 4 whereina roll of polyvinyl chloride strip material 28 is formed on an idlermandrel 30, a contact adhesive with silicone paper release tape roll 32is formed on a separate idler mandrel 34 and the formed edging strip 2is taken up on a driven mandrel 36. Pressure application rolls 38 areprovided to secure the paper release tape to the edging strip and alinear groove adjustable depth embossing roll assembly 40 is provided toform the score line 4.

In operation, the driven mandrel 36 pulls the polyvinyl chloride stripand release paper through the pressure application rolls 38 and theembossing roll assembly 40. The pressure application rolls 38 secure thecontact adhesive with silicone paper release strips 32 to the adhesivesurface 8 of the polyvinyl chloride strip 2 and the embossing rollassembly 40 forms the score line 4 linearly in a centrally disposedlocation on the strip 2.

As best seen in FIG. 5, the embossing roll assembly is comprised of anembossing roller 42 with a continuous embossing ridge 44 and a matingroll 46 with a groove 45 corresponding to the embossing ridge 44 againstwhich the embossing ridge 44 reacts through the strip 2 to form thescore line 4.

In a variation or modification of the process for forming the corneredge strip 2 of the subject invention, slitting rolls 48 and 50 can besubstituted for the embossing roll assembly 40. The slitting rolls 48and 50, best seen in FIG. 6, are arranged to provide a depth ofapproximately 0.030 inches when applying the score line 4 to a polyvinylchloride strip 2. The effect of the slitting roll is to provide both ascore line 4 and also sever the release paper into two separate distinctstrips 12 and 14, by stretching the polyvinyl chloride strip and tearingthe release paper.

The score line 4 on the strip 2, although linearly disposed, can belocated off-center. Illustratively, in covering a two inch thick foilfaced insulation board, with a four inch corner edge strip 2, a one inchcoverage over the foil by the corner edge strip 2 is appropriate withthe remaining three inches of the corner edge strip 2 covering the twoinches of raw end insulation board and adjacent foil facing. Thus, thestrip 2 for that particular application has the linear score line 4located one inch in from an edge.

Practice has shown that polyvinyl chloride identified as rigid, highimpact strength PVC having a thickness of 0.005 inch to 0.0625 inchperforms well as the edging strip 2. However, light gauge metal of 0.005inch to 0.020 inch thickness or more can also serve as the edgingmaterial. Further, a composite of aluminum fused to rigid polyvinylchloride known as VINALUM manufactured by Proto Corporation alsoperforms well as the material of the edging strip 2. The depth of thescore line 4 is 0.010 to 0.062 inch and preferably 0.030 inch.

In another embodiment of the invention the corner edging strip maycontain a plurality of score lines 4 linearly disposed over the lengthof the strip 2 which allows for selective forming of the strip tovarious edges. For example a four inch wide strip may have five scorelines, each score line being disposed at least 1/2 inch from theadjacent score line. The score lines 4 on this embodiment would belocated 1/2, 1, 11/2, 2 and 21/2 inches from an edge of the strip 2 withthe remaining 11/2 inches of the strip 2 being unscored. The strip maythen be bent at any of the score lines to form the desired amount ofstrip material on each side of the article being edged.

The strip 2 with a plurality of score lines 4 is especially suited toedging the terminal ends of insulated pipes.

The terminal end of an insulated pipe is edged by bending the strip 2 atone of the plurality of score lines 4 to create a section of the strip 2corresponding to the thickness of the insulation on the pipe to beedged. For example, for a pipe 70 covered with 11/2 inch insulation, afour inch strip 2 with five score lines at 1/2 inch intervals would bebent at the score line that is 11/2 inches from the edge of the strip 2.The remaining 21/2 inch strip is then applied to the outer perimeter ofthe pipe insulation 72. The 11/2 inch portion of the strip 2 is thenscissor cut into discrete segments 22 by cutting slits 24 into the strip2. The discrete segments 22 are then adhered to the exposed terminal endof the pipe insulation with adjacent discrete segments overlapping asseen in FIG. 7.

Once the pipe insulation is edged the edging may be painted withPVC-type adhesive caulkings such as Celulon®, or Clear as made by RedDevil, Inc. of Union, N.J., or All Purpose Adhesive Caulk as made byMacKlanburg Duncan of Oklahoma City, Okla.

The width of strip 2 and number of score lines can be varied toaccommodate any pipe insulation thickness or length of lineal pipecovering.

According to this embodiment, one or two rolls of the edging materialmay be carried by a mechanic to cover the raw ends of pipe coveringsrather than ordering specific sized end caps or different roll sizes ofthe Roll Kiku-za type material.

Many variations of the present invention will suggest themselves tothose skilled in the art in light of the above-detailed description. Allsuch obvious modifications are within the full intended scope of theclaims.

I claim:
 1. A corner edge material, for edging and sealing the cornersof ductwork and other conduit structures, comprised of a strip of edgingmaterial, at least one linearly disposed score line extending the lengthof the strip on one side of the strip, and a layer of adhesive on theside of the strip on which the score line is present, wherein the stripis from 0.005 inches thick to 0.0625 inches thick and formed of materialfrom the group consisting of rigid, high impact grade polyvinylchloride, light gauge metal and composite of aluminum fused to rigidpolyvinyl chloride.
 2. Corner edge material as in claim 1 furthercomprising release paper covering the adhesive surface.
 3. Corner edgematerial as in claim 2, further comprising the composite strip with atleast one score line, adhesive material and pressure sensitive releasepaper formed in a roll.
 4. Corner edge material as describe din claim 1,wherein the strip material is rigid polyvinyl chloride.
 5. Corner edgematerial as in claim 1, wherein the strip material is light gauge metal.6. Corner edge material as in claim 1, further comprising the materialof the strip being formed of aluminum fused to rigid polyvinyl chloride.7. Corner edge material as in claim 1, wherein the score line isparallel with both edges of the strip and located an unequal distancefrom the edges of the strip.
 8. Corner edge material as in claim 1,wherein the score lien is parallel with both edges of the strip andlocated an equal distance from the edges of the strip.
 9. Corner edgematerial as in claim 2 further comprising discrete strips of releasepaper separated at the score line.
 10. Corner edge material as in claim9 further comprising a plurality of parallel score lines.
 11. Corneredge material as in claim 10 wherein the score liens are equidistantfrom each other.